>> A = [10, 23, 90, 125, 145, 250];
B = char(A)
Error: Character vector is not terminated properly.
isn't at all the same thing as
>> C = ' Z}ú';
>> D = double(C)
You had to convert the linefeed ASCII 10 that was displayed as newline action on the command window into a blank to store it into variable C and so when you convert that string to double you reflect that modification to the original data.
>> B = char(A);
which conclusively illustrates that what is displayed on the terminal screen isn't what is stored in memory. Certain non-printing characters have definite meanings in use to perform actions on the hardware; a char(10) is one of those.